1. Field of the Invention
The present invention relates to a heat exchanger for a dehumidifier using a liquid desiccant and a dehumidifier using a liquid desiccant having the same, and particularly, to a dehumidifier capable of absorbing moisture from the air by using a liquid desiccant, and a heat exchanger for the dehumidifier.
2. Background of the Invention
A dehumidifier using a liquid desiccant is an apparatus for obtaining dry air by absorbing moisture from the air by spraying a liquid desiccant having a high concentration to the air. The dehumidifier using a liquid desiccant is configured to be consecutively operated by circulating a liquid desiccant sprayed into the air, an object to be dried. Since the liquid desiccant having absorbed moisture from the air becomes dilute, an absorbing characteristic of the liquid desiccant in the next cycle is lowered. To prevent this, the moisture included in the liquid desiccant is made to be evaporated in a high-temperature atmosphere by re-spraying the liquid desiccant having absorbed the moisture from the high-temperature regeneration air, which is called as a ‘regeneration’ process. The regeneration process is performed in a regenerator.
In order to enhance dehumidifying efficiency in the dehumidifying process, it is advantageous for the liquid desiccant and the air to which the liquid desiccant is sprayed to have low temperature. Here, it is also advantageous to increase a contact area between the liquid desiccant and the air. On the other hand, in the regeneration process, the liquid desiccant and the air to which the liquid desiccant is sprayed have to have a high temperature, and a contact area therebetween has to be increased. In order to operate the dehumidifier using a liquid desiccant, the air and the liquid desiccant need to be heated (regeneration process), or cooled (dehumidification process). For the regeneration process and the dehumidification process, a heat exchanger is required.
More concretely, the liquid desiccant and the air may be cooled or heated is through heat exchange with a heat transfer medium having a high or low temperature and flowing in the heat exchanger, by spraying the liquid desiccant and the air to the surface of the heat exchanger, and thus by making the liquid desiccant flow along the surface of the heat exchanger. In order to cool or heat a larger amount of liquid desiccant per hour, a larger amount of liquid desiccant has to be supplied. However, in this case, the liquid desiccant may form a thick liquid film on the surface of the heat exchanger, thereby lowering heat and mass transfer coefficient. Furthermore, waves may be formed on the surface of the liquid film, or the liquid desiccant may spread to the air due to the unstable liquid film.
FIG. 1 shows a heat exchanger in accordance with the conventional art. Referring to FIG. 1, the heat exchanger 10 has a structure that a plurality of heat exchanger bodies 12 are arranged in parallel. Cooling water or heating water for heat exchanger flows at an inner space of each of the heat exchanger bodies 12. The inner space is divided into a plurality of channels by partition walls 14. A liquid desiccant is supplied to the heat exchanger 10 along the surfaces of the heat exchanger bodies 12. The liquid desiccant is supplied from the upper side of the heat exchanger bodies 12, and is downwardly moved along the surfaces of the heat exchanger bodies 12 by gravity. And, the air or regeneration air is supplied to a space between the heat exchanger bodies 12.
Since the liquid desiccant and the air is heated or cooled, dehumidifying efficiency or regeneration efficiency may be enhanced. Under these structures, the liquid desiccant has to be uniformly supplied to the heat exchanger 10 along the surfaces of the heat exchanger bodies 12. And, the liquid film has to have a thin thickness so as to increase a heat transfer amount to the air, and to prevent the liquid desiccant from dispersing to the air.
Substantial heat exchange between the liquid desiccant and the air is performed on the surfaces of the heat exchanger bodies 12. This may cause the heat exchanger to have a large size. Furthermore, due to limitations in the thickness of the liquid film, a heat transfer amount per hour may be reduced.